The present invention relates to a Universal Serial Bus (hereinafter USB) hub, and more particularly to a modular stackable component system including a base unit and one or more stackable hubs mounted to the base unit.
A personal computer system typically includes a computer, a display such as a CRT or flat panel display, and other peripheral devices communicating with the computer for entering data, printing data or controlling the computer. The peripheral devices require a connection to the computer which will enable them to communicate with the computer. Typically, most peripheral devices communicate with the computer over an individual connection cable having a corresponding connector attached to the computer.
A USB hub provides a convenient central data connection point for attaching multiple peripheral devices to a computer. The hub relays data from the computer to all enabled devices connected to the data hub, and relays data from the enabled devices to the computer. This data relay is performed without any data storage or significant delay. The USB hub is connected to the computer via a single USB upstream connector. The USB hub also includes a plurality of downstream ports for connecting the peripheral devices to the hub. The USB hub uses standardized connectors at the upstream and downstream data ports to provide universal connectivity between peripheral devices and the computer, thus simplifying these connections by eliminating different cords and connectors. The terms xe2x80x9cupstreamxe2x80x9d and xe2x80x9cdownstreamxe2x80x9d will be used in the present application in their conventional sense when referring to the transfer of data.
Conventional USB hubs receive power for low power applications via a positive voltage conductor and a ground conductor from a source, such as the computer, through the upstream port. Conventional USB hubs are also equipped with a connector for connecting with a transformer plugged into a typical AC outlet for providing DC power to the hub for high power applications. The terms xe2x80x9cupstreamxe2x80x9d and xe2x80x9cdownstreamxe2x80x9d will be also be used in the present application in their conventional sense when referring to the transfer of power for low power and high power applications to a single hub.
When more than one conventional USB hub is used, each hub is connected to a separate transformer for high power applications, resulting in a clutter of cords, transformers, and used outlets. It is desirable to simplify the connection of multiple USB hubs, thereby reducing the number of cords and transformers needed, as well as providing a more space efficient footprint, by providing a system having a base with a power supply to which hubs of all types can be mechanically and electrically attached by stacking the hubs one on top of the other.
The base will be the xe2x80x9cmostxe2x80x9d downstream point as far as the power being supplied by the system is concerned. The first xe2x80x9chubxe2x80x9d stacked on the base, and mechanically and electrically connected thereto, will be sometimes referred to as being xe2x80x9cupstreamxe2x80x9d of the base unit, and the next xe2x80x9chubxe2x80x9d will be further upstream, etc., and xe2x80x9chubsxe2x80x9d which are closer to the base will be sometimes referred to as xe2x80x9cdownstreamxe2x80x9d of xe2x80x9chubsxe2x80x9d which are farther from the base, it should be understood that the direction of power transfer is only xe2x80x9cupstreamxe2x80x9d from the base unit. There is no power transfer from a xe2x80x9chubxe2x80x9d downstream to the base unit.
A modular stackable USB hub system includes a base unit having a suitable power supply therein. The power supply is connected to a first or top power port for supplying power to a stackable USB hub releasably connected to the base.
A stackable USB hub having a first or top power port for accepting other upstream components in a stackable component system is also provided. The first or top power port includes a first or top power port connector, a voltage conductor and ground conductor for providing voltage and ground to an upstream component to supply the high current requirements of the component hub in high power applications, thereby eliminating the need for a separate transformer for the USB hub in high power applications.
The stackable USB hub further includes a second or bottom power port for connecting or mounting to other components in the modular stackable component system, such as a base unit or a downstream hub. The second or bottom power port includes a second or bottom power port connector, a voltage conductor and a ground conductor. The voltage and ground conductors are connected to the respective voltage and ground conductors of the USB first or top power port connector for passing voltage and ground to the upstream component connected to the hub, as well as to the circuit or circuit board in the stackable component, thereby eliminating the need for a separate transformer for each component of the system. The stackable configuration also reduces the footprint of the system. It should be understood that the voltage and ground conductors, while a part of the power port, do not physically need to be part of the power port connector.